Q. What is AIDS? What causes AIDS?
A positive HIV test result does not mean that a
person has AIDS. A diagnosis of AIDS is made by a
physician using certain clinical criteria (e.g., AIDS
indicator illnesses).
Infection with HIV can weaken the immune
system to the point that it has difficulty
fighting off certain
infections. These types of infections are known as
"opportunistic" infections because they take the
opportunity a weakened immune system gives to
cause illness. Many of the infections that cause
problems or may be life-threatening for people
with AIDS are usually controlled by a healthy
immune system. The immune system of a person
with AIDS is weakened to the point that medical
intervention may be necessary to prevent or treat
serious illness.
Today there are medical treatments that can slow
down the rate at which HIV weakens the immune
system. There are other treatments that
can prevent or cure some of the illnesses
associated with AIDS. As with other diseases, early
detection offers more options for treatment and
preventative care.
Q. Where did HIV come from?
We do know that the virus has existed in the
United States since at least the mid- to late 1970s.
From 1979-1981 rare types of pneumonia, cancer,
and other illnesses were being reported by doctors
in Los Angeles and New York among a number of
gay male patients. These were conditions not
usually found in people with healthy immune
systems.
In 1982 public health officials began to use the
term "acquired immunodeficiency syndrome," or
AIDS, to describe the occurrences of opportunistic
infections, Kaposi's sarcoma, and Pneumocystis
carinii pneumonia in previously healthy men.
Formal tracking (surveillance) of AIDS cases
began that year in the United States.
The cause of AIDS is a virus that scientists isolated
in 1983. The virus was at first named HTLV-III/LAV
(human T-cell lymphotropic virus-type
III/lymphadenopathy- associated virus) by an
international scientific committee. This name was
later changed to HIV (human immunodeficiency
virus).
Q. How does HIV cause AIDS?
infection. Most of these people will develop AIDS as a
result of their HIV infection.
Ans. HIV destroys a certain kind of blood cells--
CD4+ T cells (helper cells)--which are crucial to
the normal function of the human immune
system. In fact, loss of these cells in people with
HIV is an extremely powerful predictor of the
development of AIDS. Studies of thousands of
people have revealed that most people infected
with HIV carry the virus for years before enough
damage is done to the immune system for AIDS to
develop. However, recently developed sensitive
tests have shown a strong connection between
the amount of HIV in the blood and the decline in
CD4+ T cell numbers and the development of
AIDS. Reducing the amount
Ans. We do not know. Scientists have different
theories about the origin of HIV, but none have
been proven. The earliest known case of HIV was
from a blood sample collected in 1959 from a man
in Kinshasha, Democratic Republic of Congo.
(How he became infected is not known.) Genetic
analysis of this blood sample suggests that HIV-1
may have stemmed from a single virus in the late
1940s or early 1950s.